5/25/08 DISC: TX/OK/KS/NE/AR/MO/IL/IA/MN/WI/CA

[rdale]

FYI: Houses can be EF5...can go to 220 MPH (max) with a cleaned slab (DOD FR12, DI 10).

DOD FR12 - DI 10 = a max of 198mph, not 220mph. That's EF4 range.

http://www.spc.noaa.gov/efscale/2.html

 

[Van DeWald]

Hmm, that's curiuos. The original EF Scale document has a different table for FR12, which shows DOD 10 from 165 to 220 mph, on page 8 of this document: http://www.wind.ttu.edu/EFScale.pdf If using that scale, then DOD10 for FR12 would correlate to EF5 damage. I wonder if the scale was notched down. I'll have to dig to find out...

Van

 

[Kevin Crawmer]

We were chasing in SW KS yesterday and caught the Bison, KS tornado and the large rotating wall cloud in LaCrosse. There were more funnels and rotating wall clouds to count yesterday and we were thinking that the surrounding storms outflow was ruining the nice inflow these storms were getting. There was great low level convergence going on and the inflow winds were strong, but storms to the north could have been stealing their thunder.

We chased in NE on Sat and KS on Sun and it was my first chase in the plains. The experience was unbelievable. The scenery of some of the old abandoned farms and ghost towns was incredible. Beautiful countryside.

On our way back to MO/IL now. Photos in the report threads tonight or tomorrow.

 

[Tony Lyza]

Hmm, that's curiuos. The original EF Scale document has a different table for FR12, which shows DOD 10 from 165 to 220 mph, on page 8 of this document: http://www.wind.ttu.edu/EFScale.pdf If using that scale, then DOD10 for FR12 would correlate to EF5 damage. I wonder if the scale was notched down. I'll have to dig to find out...

Van

It was notched upward. Rob's numbers were from the original publication. They were revised after the discrepancy between the EF scale and F scale wrt single-family homes was realized.

 

[rdale]

Someone should let SPC know -- that really could screw up the damage scale if different areas of NWS are using different numbers!

 

[Van DeWald]

Tony, Rob,

I've contacted the WCM at the SPC to find out which version is correct. It seems that SPC webpage may still referencing version 1 of the scale, which is based on the June 2004 document. But there is a version 2 of the scale, which is dated October 2006. Haven't heard back yet.

Van

 

[Kiel Ortega]

The latest EF-kit from the Warning Decision Training Branch (which is what I think most of the NWSFOs use) is up-to-date with the FR12, DOD10 going to 220 MPH.

 

[rdale]

Thanks - I couldn't find a public link for that from their webpage but managed to get a hold of one. I do see the differences.

There should be an "official repository" somewhere so that everybody is on the same page...

 

[Dean Baron]

Hugo, MN tornado rated EF-3, the Blaine-Coon Rapids, MN tornado rated EF-1.

 

[Derek Weston]

Preliminary report on the Parkersburg tornado is out. 43 mile path length, 1.2 miles at its widest.

Official rating coming sometime tomorrow, but they're saying 'potentially greater than EF3' -- this isn't too hard to imagine.

http://www.crh.noaa.gov/crnews/display_story.php?wfo=dmx&storyid=14896&source=0

 

[Joel Wright]

Preliminary report on the Parkersburg tornado is out. 43 mile path length, 1.2 miles at its widest.

Official rating coming sometime tomorrow, but they're saying 'potentially greater than EF3' -- this isn't too hard to imagine.

http://www.crh.noaa.gov/crnews/display_story.php?wfo=dmx&storyid=14896&source=0

None of the images show up for me. All just red x.

 

[John Peters]

None of the images show up for me. All just red x.

I'm sure they just haven't had time to update the website yet. It seems like most of the "at least EF-3" cases ultimately result in higher ratings.

 

[Josh Richardson]

As a fellow North Iowan I just wanted to thank everyone who did an outstanding job of relaying the info to DMX beginning around the Ackley area. Most of us chasing that day were still on the northern warned storm and from what I could see on spotter network we all werent even heading to that storm until it was already going through Parkersburg or already passed. It seemed most of us probably didnt catch up until right before Waterloo or just thereafter. So for all you who happened to be on the southern storm early I just wanted to reiterate the thanks from many people up here. It is without a doubt the early warnings did prevent the fatality totals from being much higher.

 

[Scott Lincoln]

From what I understand the "possibly greater than EF3" rating is somewhat of a 'policy' when thinking of going EF4-5. Meteorologists from DMX have been quoted as saying that a EF4-5 rating is probable. There are houses shown in the survey from Iowa Helicopter than are clean to the foundation - and no debris on site... its all just gone. There are several houses like this. If they were homes of good construction, it will almost have to be EF5. John McLaughlin on KCCI-tv is giving the impression that he believes EF5 after going up in his helicopter (which he does often with DMX), as he basically stated that "it takes winds of 200mph or greater" to do the damage he's seen.

http://mesonet.agron.iastate.edu/cases/080525/

Some areas I think will be looked at again today for EF4-5 consideration:
http://mesonet.agron.iastate.edu/cases/080525/iowa_helicopter_survey/IMG_6369.jpg
http://mesonet.agron.iastate.edu/cases/080525/iowa_helicopter_survey/IMG_6391.jpg
http://mesonet.agron.iastate.edu/cases/080525/iowa_helicopter_survey/IMG_6420.jpg
http://mesonet.agron.iastate.edu/cases/080525/iowa_helicopter_survey/IMG_6441.jpg
http://mesonet.agron.iastate.edu/cases/080525/iowa_helicopter_survey/IMG_6446.jpg

 

[Van DeWald]

For those that don't know, a 'QRT' is short for "Quick Response Team." Basically, it's a panel of NWS experts that can effectively rate whether the damage qualifies as EF5 or not. Currently, local NWS officials (WCM, MIC, etc) can occasionally rate EF4 damage without a QRT, but for EF5 damage, a QRT is required. Thus, until the QRT can assemble and assess the damage, the standard company line is "greater than EF3" damage.

Van